Cognitive enhancement of different cereals fermented by Lactobacillus rhamnosus in mice

Cereal fermentation can markedly enhance both the nutritional and functional properties of grains. In this study, we systematically compared the compositional and functional properties, particularly the cognitive benefits, of three cereals (rice, foxtail millet and oats) fermented with Lactobacillus rhamnosus . Fermentation significantly increased the total phenolic and flavonoid contents in rice and oat flours, while fermented oat flour yielded substantial amounts of short-chain fatty acids. Untargeted metabolomic analysis revealed that L. rhamnosus induced distinct metabolite changes depending on the cereal substrate, with the greatest number of differential metabolites observed in the fermented rice flour. Consistently, the fermented rice flour possessed the strongest DPPH and hydroxyl radical scavenging activities. Furthermore, in vivo behavioral tests demonstrated that all fermented cereals enhanced spatial memory in mice, fermented oats notably improved novel object recognition ability, and fermented rice and oats strengthened fear memory. Overall, this study demonstrates that cereal fermentation enhances nutritional and functional attributes, while highlighting the importance of considering the interaction between microbial strains and cereal substrates.